HETEROPHASE GROUND DETECTION SYSTEM

PURPOSE:To specify a ground-fault generating section by providing a plurality of slave stations outputting the operation statuses of zero-phase overcurrent relays at every section and a ground directional relay and a master station receiving the signals of the slave stations in a power distribution system partitioned into a plurality of sections. CONSTITUTION:In a power distribution system composed of a bus 1 and distribution lines 21, 22, zero-phase current transformers ZCT 511... and slave stations 911... are provided at every section 11... Each slave station 911... has ground directional relays 611... and zero-phase overcurrent relays 711... A master station 14 collects the operation statuses of the relays transmitted from the slave stations 911... through a communication line 13. When a ground fault is generated, the master station 14 receives a signal from the corresponding slave station and interrupts a corresponding circuit breaker 41 or 42 while investigating a response signal from another slave station, and specifies a ground-fault generating section from the operation status of the relay of the adjacent slave station. Accordingly, fault sections can be specified even in faults simultaneously generated in different distribution lines.